Radio Shack Pro-76, Pro-79, Pro-82, Pro-89, Pro-2016 and Pro-2017

The scanner end of the cable is a standard 3.5mm (1/8") Phone Connector. The computer end of the cable is a standard female DB9 connector. The sleeve (bottom section) of the phone connector is the ground and is connected to pin 5 (GND) of the DB9 connector. The ring (middle section) of the phone connector is receive data (RXD) for the scanner and is connected to pin 3 of the DB9 connector which is transfer data (TXD) for the computer. The tip (top section) of the phone connector is mono audio, for when headphones are connected, and is not connected to the computer end of the cable.